Adjustable jump stitch attachment



United States Patent Paul D. PeII;

Richard P. Benedict, Grand Haven, Michigan Jan. 13, 1969 Nov. 10, 1970 Grand Haven Screw Products Grand Haven, Michigan a corporation of Michigan Inventors Appl. No. Filed Patented Assignee ADJUSTABLE JUMP STITCH ATTACHMENT 9 Claims, 4 Drawing Figs.

US. Cl .4 112/239 Int.Cl ....D05b29/00 FieIdofSearchWHH 1. 112/239, 238,235

[56] References Cited UNITED STATES PATENTS 1,280,947 10/1918 Beckwith 112/239 2,562,771 7/1951 Chicketti 112/239 2,576,357 11/1951 Preston 1.. 112/239 Primarv Examiner-Patrick D. Lawson AttornevPrice, Heneveld, Huizenga & Cooper ABSTRACT: This disclosure relates to an adjustable jump stitch attachment for a sewing machine. The attachment has a body which is fixed to an upper part of the presser foot bar, and has cross pin means rotatably mounted on the body for engaging the needle bar mechanism during a portion ofits lifting cycle to lift the presser foot synchronously therewith. The cross pin means have outer surfaces which contact the needle bar mechanism at different distances above the body so that the extent to which the presser foot is raised by the cross pin means is adjustable.

ADJUSTABLE JUMP STITCH ATTACHMENT DISCLOSURE This invention relates to an adjustable jump stitch attachment for sewing machines for raising the presser foot in synchronism with the lifting of the needle so as to permit thicker materials to be more easily sewn by the machine.

Devices for sewing machines, such as patching machines, have been devised to raise the presser foot synchronously with the raising of the needle so as to permit thicker material, such as leather to be sewn, and to permit work to be manually manipulated during the sewing to accomplish herringbone and other type patterns. Preston US. Pat. No. 2,576,357 discloses one such device. The attachment of Preston has an L-shaped arm which is spring biased in a tube and fixed onto the top of the presser foot bar. One end of the arm is adapted to extend over and contact the needle bar actuating mechanism as it lifts the needle thereby raising the presser foot. In this device as in others, the arm is subject to bending and only has one lifting distance for the presser foot.

I have now discovered an improved sewing machine jump stitch attachment which has a plurality of arms for lifting the presser foot to different heights and by its construction is inherently resistant to bending.

By various aspects of this invention one or more of the following, or other, objects can be obtained.

It is an object of this invention to provide an improved jump stitch attachment mechanism for sewing machines wherein the presser foot can be raised synchronously with the raising of the needle to different heights.

It is a further object of this invention to provide a jump stitch attachment for patching machines and the like, the construction of which attachment is strong and bend resistant.

It is a still further object of this invention to provide an improved jump stitch attachment for sewing machines, which attachment is quickly and easily applied to existing machines with minimum modification to the machines.

Other aspects, objects, and the several advantages of this invention are apparent to one skilled in the art from a study of this disclosure, the drawings, and the appended claims.

According to the invention, there is provided an attachment for a sewing machine having a presser foot and a needle bar actuating mechanism. The attachment causes the lifting of the presser foot in synchronized movement with the needle bar actuating mechanism. The attachment comprises a body, means on the body for engaging a top portion of the presser foot and a cross pin means rotatably fixed to the body. The cross pin means have arms adapted to extend outwardly over the needle bar actuating mechanism when the body is fixed to the presser foot bar, the arms having bottom surfaces adapted to contact the needle bar actuating mechanism at different distances above the body.

The invention will now be described with reference to the accompanying drawings in which:

FIG. I is a perspective view of a jump stitch attachment according to the invention as fixed onto a sewing machine;

FIG. 2 is a front view of the attachment on a sewing machine shown in FIG. 1;

FIG. 3 is an enlarged sectional view of the jump stitch at tachment affixed to a sewing machine; and

FIG. 4 is an enlarged view, like FIG. 3, showing a modified form of the invention.

Referring now to FIGS. I3, there is provided a sewing machine 12 having a machine head 14 with a reciprocating walking beam 16 to drive a needle bar 18 and a needle 22. The needle bar is rotatably fixed to the walking beam through a pin 20. A work supporting horn 24 is positioned beneath the sewing machine head 14 and houses a feed dog (not shown).

A presser foot 26 is provided for pressing the work firmly against the horn 24. The presser foot 26 is fixed to a presser foot bar 28 which extends through the machine head 14 and is connected to a crosshead 30. Vertically extending holes in the crosshead 30 permit the crosshead to slide vertically on the needle bar 18 and on a thread tension shaft 32. The thread passes around the thread tension shaft 32, through the eye in the thread takeup lever 33 (shown only in FIG. I) and down the needle bar 18 to needle 22. Tension on the presser foot 26 is maintained by conventional means (not shown). As is common in patching machine, the presser foot is raised slightly as the needle bar 18 reciprocates to permit the work to be moved by the feed dog when the needle is raised.

The foregoing has been a description of a conventional sewing machine such as a Singer sewing machine or an Adler sewing machine.

According to the invention, a jump stitch attachment 34 is fixed to the presser foot bar 28 to raise the presser foot 26 with the raising of the needle 22 to permit stitching of heavier work. The attachment raises the presser foot higher than normally done by the conventional machines. The operation of the jump stitch attachment in synchronism with the raising of the needle bar 18 is illustrated in phantom lines in FIG. 2.

The jumpstitch attachment comprises a body 36, a shaft 38 which fixedly houses a cross pin 42 Ma lateral bore 40. The outer extremities of the cross pin 42 contact the top portion of the walking beam 16 as the walking beam is lifted. The cross pin 42 is cut away beneath one end at 44.

The body 36 has a central bore 46, a closed end 48 with an aperture 50 permitting the passage of shaft 38 therethrough. A head 52 of shaft 38 is slideable within the central bore 46 but is retained within the bore by the closed end 48. A spring 54 is biased at one end against the head 52 and at the other end against an insert 56 which is fixed in the bottom of the body 36 A pin 62 extending through the body 36 and into the insert 56 retains the insert 56 within the bottom of the body 36.

The central bore 58 of the insert 56 is topped so as to threadably engage a stud 60 on the top of presser foot bar 28. In other words, the jump stitch attachment holds crosshead 30 onto the presser foot bar 28 through a threaded stud 60.

In operation, the sewing machine is used normally with the cross pin 42 turned from that position as shown in FIG. 2. In this position, the presser foot 26 will be actuated only by the normal presser foot actuating devices (not shown). In the event that thicker material is to be stitched, it is desirable to lift the presser foot 26 to a greater extent than normal as the needle 22 is lifted. For this purpose, the cross pin 42 is rotated to the position illustrated in FIG. 2. At this point, when the walking beam 16 and the needle bar 18 are raised, they will contact the cutaway portion 44 of the cross pin 42 to raise the presser foot 26, as illustrated in FIG. 2 in phantom lines, each time the walking beam 16 raises the needle bar 18. In this manner, the thicker material can be easily moved during the stitching operation.

In the event that the presser foot 26 must be raised a still greater amount than that permitted by the arrangement illustrated in FIG. 2, the shaft 38 and the cross pin 42 can be rotated through l80 so that the other end of the cross pin 42 (opposite the cutaway portion 44) is above the needle bar 18. In this instance, the presser foot will then be raised further a distance in the amount equal exactly to the radius of the cross pin 42. Thus, the presser foot attachment is adjustable between two positions by merely rotating the crossbar 42 through In the event that finer adjustments are required, the body 36 can be raised or lowered with respect to the threaded stud 60 to achieve a finer adjustment. In other words the threaded engagement of the jump stitch attachment with the presser foot rod provides a fine adjustment for the jump stitch device. The ability of the shaft 38 to turn without turning the body 36 permits the fine adjustment to be maintained regardless of the number or direction of turns of shaft 38.

Normally, the Singer sewing machine has stud 60 fixed to cross head 30 by a bolt which threadably engages stud 60. When the jump stitch attachment is to be added, the bolt is unscrewed and the attachment 34 is screwed onto stud 60 in place of the bolt. The attachment is thus easily fixed on a Singer sewing machine with a minimum of modification and without elaborate tools.

ln the alternate embodiment shown in FIG. all of the parts are identical except that the top of the presser foot rod 28 has a threaded bore 70 in which there is positioned a threaded shaft 68 on a stud 66. The central bore of the insert 56 is not threaded but retains the head of stud 66 through a knurled and pressed fitting. The operation of the device is identical to that illustrated in FIGS. 1 through 3. This device shown in FIG. 4 is particularly adapted for the Adler sewing machines whereas the device shown FIG. 3 is more adapted for the Singer sewing machines.

in the Adler sewing machines, the crosshead is fixed to the presser foot bar 28 through a screw which engages the threaded bore 70. The attachment shown in FIG. 4 is fixed to the Adler sewing machine by removing the screw in bore 70 and screwing stud 68 of the attachment into the bore 70. The modified form of the invention is easily fixed to the Adler sewing machine with a minimum of modification to the machine and without elaborate tools.

Due to the construction of the attachment, the cross pin 42 is inherently resistant to bending. The shaft 38 and the cross pin 42 can be made of strong bar stock which is highly resistant to bending. In the prior art devices, the arms which contacted the needle bar actuating mechanism had to be bent in order to contact the same. Thus the material used was much weaker than that which can be used by the construction according to the invention.

Reasonable variation and modification are possible within the scope of the foregoing disclosure and drawings without departing from the spirit of the invention.

We claim:

1. in combination with a sewing machine having a presser foot bar guided for vertical reciprocation in a sewing machine head, means on said sewing machine head for urging the presser foot downwardly against the work but yicldable upwardly therefrom, needle bar reciprocating drive mechanism, presser foot lifting means synchronized with the lifting of said needle bar reciprocating drive member, the improvement in said presser foot lifting means comprising:

a body;

means for fixing said body onto a top portion of said presser foot bar; and

cross pin means mounted on said body, said cross pin means including outwardly extending arms having bottom surfaces adapted to contact said needle bar reciprocating drive mechanism at different distances above said body as said drive mechanism is raised, whereby said presser foot can be lifted by said needle barrecipr-acating drive mechanism to different heights as said needle bar is raised. 2. The combination of claim 1 wherein said body is threadably attached to said upper portion of said presser foot bar so as to provide fine adjustment of said cross pin means relative to said needle bar reciprocating means.

3. An attachment for a sewing machine having a presser foot bar supporting apresser foot, and a needle bar actuating mechanism, said attachment causing the lifting of said presser foot in synchronized movement with the movement of said needle bar actuating mechanism, said attachment comprising:

a body; means on said body for engaging a tap portion of said presser foot bar;

cross pin means fixed to said body, said cross pin means having arms adapted to extend outwardly over said needle bar actuating mechanism when said body is fixed to said presser foot bar; and

said arms having bottom surfaces adapted to contact said needle bar actuating mechanism at different distances above said body.

4 The invention defined in claim 3 wherein said cross pin means is rotatably mounted on said body.

5. The invention defined in claim 3 wherein said cross pin means comprises an upright bar member and a horizontal bar member ri idly joined together forming a T, the ends of said horizontal ar member forming said surfaces adapted to contact said needle bar actuating mechanism, one of said ends having a bottom portion thereof cut away so as to form a needle bar actuating mechanism contacting surface.

6. An attachment according to claim 3 wherein said engaging meansof said body comprises a tapped hole.

7. An attachment according to claim 3 wherein said engaging means of said body comprises a threaded stud.

8. The invention defined in claim I wherein said cross pin means is rotatably mounted on said body.

9. The invention defined in claim 1 wherein said cross pin means comprises an upright bar member and a horizontal bar member rigidly joined together forming a T, the ends of said horizontal bar member forming said surfaces adapted to contact said needle bar actuating mechanism, one of said ends having a bottom portion thereof cutaway so as to form a needie bar actuating mechanism contacting surface. 

